Suction packaging method



. SUCTION PACKAGING METHOD Filed Dec. 21, 1961 2 Sheets-Sheet 1 I Ill g t fiv%gon fiicgara 6. 79/23 24 M, WW

Nov. 9; 1965 R. 6. KING 3,216,832'

SUCTION PACKAGING METHOD Filed Dec. 21, 1961 2 Sheets-Sheet 2 INVEN TOR.

Pz'C/g ara Q ritzy M, M49 WM Qif'ya United States Patent 3,216,832 Patented Nov. 9, 1965 In the field of stretch wrapping, or packaging products in film, it is sometimes desirable to suck air out of the package after it is initially formed, and then seal the package so that the product is protected from contact with air. Machines for performing such suction packaging have been satisfactorily built and operated before the present invention.

According to the present invention, a method of packaging is developed by which such machines are made more efiicient and more satisfactory for some products of irregular shape, typified by a plurality of sausages. This is accomplished by premolding the package-forming films to the irregular shape of such products. By premolding the film to substantially its desired shape before evacuation thereof is commenced there is less interstitial space from which the air must be drawn, and more certainty of adequate evacuation. In the illustrated apparatus for performing my method, and which also embodies my invention, the premolding of the film is accomplished by providing ribs along the previously smooth mold surfaces, these ribs conforming to the shape of the product to be packaged.

This contour premolding increases etficiency in reducing the amount of power required for pumping. It also makes possible the allowance of less time for the evacuating of the package and therefore a speeding up of the packaging process.

It also results in better keeping qualities. It should be understood that with respect to many products, as for example, many foods, one of the reasons for the removal of air from the package is to improve the keeping qualities of the product. Often the oxygen in the atmosphere has a deleterious effect upon the product. In the past it has been assumed that an effective job of oxygen removal has been accomplished in vacuum packaging when the films of the finished package appeared to have been satisfactorily drawn into contact with the surfaces of the product. According to the present invention, however, it has been recognized that this is not always true with irregularly shaped articles; and the preshaping method of this invention gives adequate evacuation more reliably. It also facilitates separating the items within one package, when desired.

The present invention also results more reliably in the desired package attractiveness. It avoids wrinkles, which have previously occurred and avoids some instances of flattening of the product.

Additional objects and advantages of the invention will be apparent from the following description and from the drawings.

Designation of figures FIGURE 1 is a perspective view of one form of package which can be more efiiciently produced according to the present invention.

FIGURE 2 is a vertical sectional view through a mold FIGURE 5 is a vertical sectional view taken approximately about the line 55 of FIG. 3.

FIGURE 5A is a fragmentary view showing the contouring of the ends of the mold recesses in FIG. 5.

FIGURE 6 is a plan View of a mold contoured for a different article, with the article being packaged therein.

FIGURE 7 is a vertical sectional view taken approximately along the line 77 of FIG. 6, showing especially the cross section of the contoured bottom plate of the mold.

General descriptionbackground The method of this invention is best explained by reference to its performance in specific apparatus. In many respects the apparatus may correspond to that shown in the Charles E. Cloud patent, 2,888,787. FIG. 1 represents a type of package which might be formed on the machine of that patent, but which is better formed by the present method. In the illustration, the product comprises five frankturters 11. They are packaged between two films 12 and 13 of stretch-wrap material which are sealed together peripherally. Air has been evacuated from the package to draw the film into snug engagement with the product.

Although FIG. 2 includes features of the present invention, it also includes the basic features taught by the Cloud patent. Thus, a lower or base mold 14 forms a pocket into which the lower film 13 is drawn so that a pocket is also formed in it. After the product is placed in this pocket the upper film 12 is sealed across it. A perforation 16 is formed in the upper film 12 in alignment with a venting notch 17 formed in the lower film by virtue of its following the contour of a similar notch in the mold 14. A cover plate 18 is now laid across the mold 14 sealing it off, and air from within the package, that is, from between the films 12 and 13, is drawn out through suction hose 19, passage 21, perforation 16 and notch 17. During this evacuation, the same high vacuum may be applied to base mold 14 through tube 22, which would have 'been used earlier with a lower vacuum for sucking the film 13 into the mold. After the air has been evacuated from the package, air is admitted through tube 22 to collapse the package and seal lower film 13 over perforation 16, thereby sealing the package against the readmission of air.

As illustrated in the patent, the bottom of the mold was fiat and hence the lower film 13 was drawn to the shape of a flat-bottomed pocket. Likewise the cap plate 18 was flat on its inner side.

The Cloud type of machine worked very well on the types of product illustrated in that patent. On other types of product, the Cloud machine did not seem to work as perfectly.

Contour premoldz'ng According to the preesnt invention the causes of imperfections in operation of the Cloud machine with some types of packages has been recognized, and a remedy for the trouble has been provided. The trouble arose from the fact that there were depressions in the outer surfaces of some types of products. In the finished product the film obviously had been drawn into these depressions by vacuum, and the cause of imperfections was not readily determined. Even after observing that sometimes the evacuation did not seem to be as good as desired, there was still a problem of how to make it better. present invention, these causes have been determined to be mainly of three related natures.

(1) The depressions increased the amount of vacant space within the package from which air had to be withdrawn, and accordingly it increased the amount of air to be According to the withdrawn. Time which was sufficient for withdrawing the air from other packages was not sufiicient for withdrawing the air from these packages.

(2) Partly because of inadequate evacuation time, and partly for other reasons, the films did not contact the surfaces of the product as uniformly as in the case of more easily packaged articles, and the resulting exposure of air within the package caused more deterioration of the packaged product than was expected of the packages from the Cloud machine.

(3) If the application of external air pressure closed the evacuation package before completing the collapse of the package it would trap slightly more residual air within the package than would otherwise be the case.

According to the present invention, these causes of trouble are reduced or substantially eliminated by preshaping the film to conform to the depressions of the product, so that there is less space to be evacuated, so that the film more readily is drawn into contact with the product even in the area of the depressions, and so that less residual oxygen is enclosed.

As seen in FIG. 2, the preshaping of the bottom film is performed by using a bottom mold plate 24 provided with upstanding ribs or ridges 26 to fit the depressions within the product, namely the spaces between the sausages. It is apparent from FIG. 2 that the lower ribs 26 have preformed the film 13, as it was drawn into the pocket, to approximately fit the lower surface of the product. Likewise, the top mold plate or cap 18 is provided with ribs 27 extending downwardly so that they also fit the depressions in the product or the spaces between the members of the product. As seen in FIG. 3, the lowering of the cap 18 over the mold will preform the upper film 12 in like manner.

It might seem, from FIG. 2, that the sausages are spaced so far apart that there would be extra space between them to be evacuated instead of less. However, as seen in FIG. 3, the fingers 26 and 27 press the respective films 12 and 13 almost into contact with one another. Hence, there is only a very minimum space, in the end, to be evacuated.

FIGURES and 5A show other views of the structure in FIGS. 2 and 3, showing especially the partly spherical contouring of the bottom plate 24 to correspond to the shape of the ends of the frankfurters. This is important, especially if film is used which does not contract elastically, to avoid wrinkles due to excess areas of material.

. According to another feature of the invention, the same contoured bottom plate 24 may be used for a single layer of sausages an in FIG. 2, or for two layers of sausages as in FIG. 4. In FIG. 4, the contoured bottom plate 24 rests on the bottom of cavity 29 of base mold 14. This provides a mold combination comprising contour bottom plate 24 and the side walls 31 of base mold 14, suitable for two layers of sausages 11. When only one layer of sausages is to be packaged, the bottom contour plate 24 is rested on a rack 33 of any suitable form which holds the contour bottom plate 24 at the right elevation for a single layer of sausages.

The rack 33 has been shown as formed of two bars 34 of the desired vertical dimension and held in proper relationship with one another by a dowel 36 which may have a press fit with the bars 34. Flow of air past the bars 34 may be ensured by grooves 37. Since the bars fit loosely, these grooves probably are not needed, and frankly their purpose may be more to show in the drawing that there is communication past the bars 34 than because of real necessity for their use.

- FIGS. 6 and 7 illustrate another shape with respect to which the contour mold concept of this invention is useful, even though it is not as easy to obtain good interfitting between the product and the contour of the mold as in the case of FIGS 1 to 5. In FIG. 6 the product is a spread-out stack of slices of food product such as cheese or meat. The spreading out is desirable for ease in separation of the slices as well as for attractiveness in the store.

Nevertheless, such spreading out or lapping presents the problem of interstitial spaces from which air must be withdrawn. As illustrated in FIG. 7, upstanding ribs 41 are provided to interfit with the contour of the sliced product to be packaged. Preferably in this case the ribs 41 are arcuate in shape, if the slices are round as seen in FIG. 3. The cap for the mold shown in FIG. 7 may be similarly provided with ribs, although these ribs would lie mainly to the right when the ribs 41 are mainly to the left.

It will be observed that in addition to having ribs 41, the contour bottom plate 42 of FIG. 7 is concave on its upper face and nonsymmetrical so as to fit the nonsymmetrical product.

Packagers often desire to have the individual products such as frankfurters sealed in isolation from one another. It might seem from FIGURE 3 that this would not result, but in fact the two films, when pressed close to one another by ribs 26 and 27, will usually be pressed together by external air pressure when applied at the end of the evacuation. As a matter of fact, it has been found that this result can be achieved, even with a simplified version of the method in which the ribs 27 are omitted, and only the lower film is pre-contoured. In this event, however, it may be necessary to use ribs a little higher than the ribs 26 as shown so as to press the film to or even a little beyond the points at which the frankfurters are closest together. The height to which the lower film 13 will need to be precontoured will depend somewhat on the stretching characteristics of the films, and especially of upper film 16.

Although this version of the method in which the upper film is not pre-contoured does not achieve the maximum advantages of the invention from the standpoint of minimizing the space to be evacuated and minimizing the residual air, it has been found to do a satisfactory job.

Even without pre-contouring the upper film, the precontouring of the lower film has proved to be extremely important. It makes a great difference in the finished package in some instances. For example, it is very diflicult without it to achieve isolation of the frankfurters from one another. It is also ditficult without at least this lower pre-contouring to avoid a flattening of the adjacent sides of the frankfurters as the collapsing process tends to squeeze them together.

Pre-contouring the bottom film makes it possible to keep the frankfurters separated and reliably avoid wrinkles in the film on that side of the sausages so that this side has an extremely attractive appearance and may well be the side chosen for display, even though the other side may not be noticeably inferior.

For proper pre -contouring it is necessary to be sure that the film is drawn fully into the mold. This may or may not result from the fact that the bottom plates 24 or 42 fit loosely in the main mold body as 14 so that air can be drawn around the edges of the bottom plates. If it is found that the film as it stretches seals off any of the pockets or recesses into which it is intended to be drawn air passages 46 should be provided at critical points. These also aid in quick collapsing of the film after evacuation.

The present invention is to be distinguished from packaging of the past in which the simplest possible shaping of the pocket happened to be the same as that of the product. Here there is special contour shaping of nonsymmetrical or irregular nature to closely fit a product (often a multipart product) which is of a non-symmetrical shape, or recessed.

Thus, in a typical performance of the method of this invention, a first film is stretched to define a pocket for receiving the product to be packaged. This pocket is contoured to the shape of the unit(s) to be packaged and is provided with ridges which correspond in shape, size and position to the recesses on one side of the unit(s). The unit(s) are then positioned in the pocket with the recesses of the unit(s) in alignment with said ridges. A second film then is contoured to fit about the top of the unit(s) resting in the pocket. The films are provided with peripheral borders that can be sealed together to form the package. Only after at least one of the films has been contoured to the product therebetween is a vacuum applied to evacuate the interior of the package. Following this evacuation and collapsing of the package by external air pressure, the package is sealed to prevent the readmission of air.

I claim:

1. The method of packaging in a plastic film a plurality of units of product of the type deleteriously affected by the presence of oxygen and of a given shape positioned in an at least partially separated arrangement forming externally exposed recesses, said method including the steps of: initially stretching a first portion of said film to define a pocket having inwardly extending portions corresponding to the externally exposed recesses defined by one side of said units when in said arrangement and with a border of said portion surrounding said pocket; thereafter depositing said units in said pocket in said arrangement; laying a second portion of film over said product and said border; pressing the second portion into face to face contact with the first portion along said border and substantially about the upper portions of said units to define a package; withdrawing air from between said two films; and sealing said package.

2. The method of packaging in a plastic film a plurality of units of product of the type deleteriously affected by the presence of oxygen and of a given shape positioned in an at least partially separated arrangement forming externally exposed recesses, said method including the steps of: initially stretching a first portion of said film to define a pocket having inwardly extending portions corresponding to the externally exposed recesses defined by one side of said units when in said arrangement and with a border of said portion surrounding said pocket; thereafter depositing said units in said pocket in said arrangement, whereby said film substantially fits about said one side of the composite units to substantially diminish the residual air between said one side and said film; laying a second portion of film over said product and said border; pressing the second portion into face to face contact with the first portion along said border and substantially about the upper portions of said units to define a package and against the top of said units With the film extending into the top recess to diminish the residual air between the second film and the top of the units; sealing said films together to define a package and providing an exhaust opening between the interior and exterior of the package; vacuumizing the package through said opening; and applying air pressure to the exterior of the package and occluding said opening.

3. The method of packaging in a plastic film a plurality of sausages positioned parallel to each other and arranged to present upper and lower faces each including the sides of a plurality of sausages, said method including the steps of: initially stretching a first part of the film to define a pocket having a plurality of recesses separated by inwardly extending portions with each recess having a shape corresponding to a side of one sausage and said portions defining a spacing between the sausages and with a border of said part surrounding said pocket, and depositing said sausages with their lower faces in said recesses; laying a second part of film over the sausages and said border; pressing said second part into face to face contact with the first part along said border and down about each sausage in the upper face with downwardly extending ribs aligned with the ribs of the first film part to define a package; and thereafter withdrawing air from said package and sealing said package.

4. The method of packaging in a plastic film a unit consisting of a plurality of shingled slices of food product, said method including the steps of: initially stretching a first part of said film to define a pocket corresponding to the shape of one side of said unit and having inwardly extending portions corresponding to the external recesses between the shingled slices with a border of said part surrounding said pocket; thereafter depositing said units in said pocket in said arrangement; laying a second portion of film over said product and said border; pressing the second portion into face to face contact with the first portion along said border substantially about the upper portions of said units to define a package; withdrawing air from between said two films; and sealing said package.

5. The method of producing a package with a plurality of products of the type deleteriously affected by the presence of oxygen therein and with the products at least partially separated in such manner that the group of products forms depressions along a lower face of the group, said method including the steps of preliminarily stretching one portion of film to form a major pocket for the group, additionally stretching some portions of the major pocket to form minor pockets within the major pocket, depositing the group in the major pocket with the articles extending individually into the minor pockets, applying a sufficient closure over the main pocket to permit evacuation thereof, sucking air from the major pocket and the minor pockets and while so doing applying external fluid pressure to press the film forming each minor pocket into better contact with the portion of the article therein and to stretch the said intermediate portions for more intimately fitting the depressions formed by the group, and completing the seal of the package to exclude air.

6. The method of packaging in a plastic film a unit of product of the type deleteriously afiected by the presence of oxygen and of a given irregular shape having relatively projecting portions, spaced apart, at least in part, said method including the steps of: initially stretching a first portion of said film to define a pocket with portions relatively deeper than a portion between them and substantially corresponding in size and shape to at least corresponding parts of said unit of product; thereafter depositing said product in said pocket; laying a second portion of film over said product; pressing said second portion into face to face contact With the first portion about said projecting portions to define a package; withdrawing air from between said two films; and sealing said package.

References Cited by the Examiner UNITED STATES PATENTS 2,621,129 12/52 Ramsbottom et al. 99-171 [2,686,129 8/54 Seiferth 99-174 2,888,787 6/59 Cloud 53-22 2,918,767 12/59 Grinstead 53112 2,935,828 5/60 Mahaify et a1 53112 2,964,889 12/ 60 Oelze et al 99174 X 3,060,652 10/62 Eckman 53-22 3,083,106 3/63 Sloan et al. 99--171 3,131,069 4/64 Goller et al. 99174 A. LOUIS MONACELL, Primary Examiner.

ABRAHAM H. WINKELSTEIN, RAYMOND JONES, Examiners. 

1. THE METHOD OF PACKAGING IN A PLASTIC FILM A PLURALITY OF UNITS OF PRODUCT OF THE TYPE DELETERIOUSLY AFFECTED BY THE PRESENCE OF OXYGEN AND OF A GIVEN SHAPE POSITIONED IN AN AT LEAST PARTIALLY SPEARATED ARRANGEMENT FORMING EXTERNALLY EXPOSED RECESSES, SAID METHOD INCLUDING THE STEPS OF: INITIALLY STRETCHING A FIRST PORTION OF SAID FILM TO DEFINE A POCKET HAVING INWARDLY EXTENDING PORTIONS CORRESPONDING TO THE EXTERNALLY EXPOSED RECESSES DEFINED BY ONE SIDE OF SAID UNITS WHEN IN SAID ARRANGEMENT AND WITH A BORDER OF SAID PORTION SURROUNDING SAID POCKET; THEREAFTER DEPOSITING SAID UNITS INSAID POCKET IN SAID ARRANGEMENT; LAYING A SECOND PORTION OF FILM OVER SAID PRODUCT AND SAID BORDER; PRESSING THE SECOND PORTION INTO FACE TO FACE CONTACT WITH THE FIRST PORTION ALONG SAID BORDER AND SUBSTANTIALLY ABOUT THE UPPER PORTIONS OF SAID UNITS TO DEFINE A PACKAGE; WITHDRAWING AIR FROM BETWEEN SAID TWO FILMS; AND SEALING SAID PACKAGE. 